Plastic pipes are almost exclusively used in lawn and landscape irrigation and sprinkler systems because of ease of installation, low price and repair. Such pipes are commonly referred to as PVC pipes because of their plastic chemical composition being of polyvinyl chloride composition material. These pipes are almost always joined by the application of an adhesive such as a solvent or cement, that is applied to the ends of the pipes and associated fittings, valves etc. then the mating pieces are pushed together to complete the connection joint between mating components of an irrigation system. Repairs of an irrigation system are usually needed to the segment of a pipe adjacent to a flow control valve or a sprinkler head because these components of an irrigation system are near or at the surface of the earth and they are damaged by vehicles driving over them, lawn mowers cutting them or other traffic that bends and or breaks them. In the case of underground mounted valves they may simply break or wear out and need replacement. In any case the most typical location for an irrigation system to be damaged is in the segment of the pipe near a valve or sprinkler head wherein the pipe is broken thus permitting an unintended flow of water from the pipe. Examination of such damage to irrigation systems has shown that the pipe is most often broken within either adjacent to a valve or sprinkler head or within a few inches thereof.
When the pipes of an irrigation system are broken the repairman is faced with two basic options either, (1), a reconstruction by removing the entire broken pipe and valve or sprinkler head and associated fitting and replacing both or, (2), by a repair by replacing the damaged end portion of the pipe along with the valve or fitting associated with the sprinkler head. Below is described the prior art reconstruction methods including the several prior art repair methods and related hardware.
In the past reconstruction of damaged irrigation systems involved removing the dirt around long sections of damaged pipe (at least 3 feet (approximately 1 meter) or more) is removed from the ground so that a new segment of pipe could be installed. In this repair process the pipe would have to be free of ground contact to permit sufficient bending of the replacement section of pipe to permit its being joined to the remaining pipe by a collar or the like and also to the replaced valve or sprinkler head and its associated fitting. This reconstruction process can involve considerable labor to dig the pipe free for an extended distance. Then when the reconstruction is completed the pipe must be buried again and the turf and or plants that were disturbed must be carefully replaced to preserve the aesthetic appearance of the location. Also, due to physical limitations of some irrigation systems involving multiple pipes or other earthen obstacles such as concrete barriers driveways barriers, driveways, walkways or foundations the described manner of repair may be very difficult if not impossible.
Additionally, in the prior reconstruction of irrigation systems the replacement of pipe sections by replacement of elongated pipe sections required extensive evacuation of water from the defective pipe section as well as its excavation from the ground allowing space for installation by bending the pipe to permit connecting by couplings and the like. Both the evacuation of water and the excavation of earth are time consuming as well as messy depending upon the local conditions. These prior art replacement pipe sections also required that the length of pipe be inserted into place be measured to an exact length so the pipe will be properly joined on both ends to the accompanying segments or fixtures of the irrigation system. This exact measurement can be time consuming and result in wasted material and time if not done with care and precision.
The prior art repair method for irrigation systems involves using a repair coupling on a small segment of the pipe adjoining the valve or sprinkler head. In this area of the prior art a small section of pipe containing the break is dug our out and a repair of coupling device is used to span the broken section of pipe. However, in practice, it has been observed that great difficulty is encountered in installing these repair coupling devices.
The available prior art patch repair devices include either external bolt on patches that can be used to temporarily repair a defective pipe system or other devices with complex multi-piece units with telescoping members. Both of these general types of repair devices have shortcomings in their installation and operation that may cause the repair to fail in time.
The external bolts on devices merely attach to the exterior of a pipe or valve or the like and clamp a seal element and a supporting structure on the exterior of the damaged portion. These external patch repair devices suffer from a distinct disadvantage because the damaged section is not removed and replaced therefore the irrigation pipe, valve, sprinkler head, or fitting may continue to erode under the seal of the patch. Because of continued eroding the repair is only temporary and a permanent patch will eventually need to be installed in the irrigation system.
The prior art of irrigation pipe repair devices in its basic form includes the simplest use of common couplings and a segment of pipe for joining the open ends of unthreaded pipe sections. A first coupling member adapted to be fitted over and adhered to an open end of one pipe section with the pipes opposite end portion extending over and beyond the end of the attached pipe. A second coupling member having a female portion at each end portion thereof is fitted over and adhered to the open end of the other pipe section with one of the female end portions extending therefrom and exposed. The free pipe end and the second coupling are simply joined together and secured by adhesive to complete repairing connection of the pipes. This irrigation pipe repair technique requires that the pipes be precisely measured and one of them be bent in such a way as to allow the couplings to be joined and moved into their final joined resting position.
The prior art also includes several pipe repair coupling devices using a hollow telescopically extendable member mounted inside a cylindrical housing. In this arrangement the cylindrical housing is connected and secured to an end of a pipe and the hollow telescopically extendable member is extended to connect with and secured by adhesive to the end of another pipe. Several variations of this general mechanical arrangement are known in the prior art with variances in construction of the connecting ends of the device and the slip joint construction of the telescopic member. In some constructions the cylindrical housing may have a protective outer sleeve for protection of the inner workings of the device and to serve as a handgrip for installation.
Considering the complexity of some of these devices they can be costly to produce and assemble as well as being subject to damage if not kept extremely clean prior to installation. In every instance these constructions include an elongated hollow cylindrical chamber that is common with the fluid carrying opening of the pipe and a piston portion of the telescopically extendable member. Seals such as o-rings are provided around the piston portion of the telescopically extendable member to seal with the interior of the elongated hollow cylindrical chamber forming a dynamic seal. When the device is installed and fluid under pressure is passed through the pipe there is a differential pressure exerted on the piston portion with the result of forcing the telescopically extendable member that forces it to be extended. When fluid pressure is no longer on the pipe there is no pressure on the piston portion of the telescopically extendable member, thus it is not forced to an extended position. Because of the pressure on and pressure off operating conditions of irrigation systems the pipes connected with this character of device will be continually stressed by the changing forces on them. As a result it has been noted that where such pipe repair devices are used the adjacent pipe sections, and connected Tee-joints, connection collars, valves and sprinkler heads may incur further damage due to the dynamic forcing action inherent with use of this character of repair device.
All of the prior art connectors have shortcomings that render them difficult to use in repairing damaged pipes of an irrigation system where the ends of the damaged pipe are either buried in the ground or otherwise immovable. Some of these devices require extensive excavation to be installed. And, other devices have extendable members that are subject to creating difficult installations or may by their inherent nature cause other problems in an irrigation piping system.